After completing the first step of the upload wizard, you'll see thumbnails of each file you uploaded. These thumbnails are clickable: this is presumably supposed to point to the full-scale version of the file, but instead links to where the file would be once the process is completed (in my case, http://commons.prototype.wikimedia.org/w/images/c/cc/Ie7fail.png ), which of course 404s.

Version: unspecified
Severity: enhancement